When a material is processed by chemical vapor deposition (CVD), reactive ion etching (RIE), or the like, topography simulation for calculating a change (e.g., development over time) in the topography of the material can be performed in advance. In the topography simulation, long calculation time may be taken to process a plurality of surface segments constituting a surface of the material or to repeatedly calculate development over time. Improvements in such topography simulation method remain desired.